annotate tests/test-transaction-rollback-on-revlog-split.t @ 50662:12f13b13f414 stable

revlog: avoid possible collision between directory and temporary index

Since 6.4, we create a temporary index file to write the split data without
overwriting the inline version too early. However, the store encoding does not
prevent these new `.i.s` file to collide with a directory with the same name.
While the odds for such a collision to happens are fairly low, the collision
would prevent Mercurial from working.

The store encoding have a mitigation solution in place to prevent such
collisions from happening for `.i` and `.d` files, but not for other extensions.
We cannot update this encoding scheme to solve the issue since it would diverge
from older version of Mercurial.

Instead, we create an alternative directory tree dedicated to such files.
The use of the `.i` extension combined with store encoding will prevent
collisions there.

Test correctness of revlog inline -> non-inline transition
----------------------------------------------------------

We test various file length and naming pattern as this created issue in the
past.

Helper extension to intercept renames and kill process

  $ cat > $TESTTMP/intercept_before_rename.py << EOF
  > import os
  > import signal
  > from mercurial import extensions, util
  > 
  > def extsetup(ui):
  >     def rename(orig, src, dest, *args, **kwargs):
  >         path = util.normpath(dest)
  >         if path.endswith(b'data/file.i'):
  >             os.kill(os.getpid(), signal.SIGKILL)
  >         return orig(src, dest, *args, **kwargs)
  >     extensions.wrapfunction(util, 'rename', rename)
  > EOF

  $ cat > $TESTTMP/intercept_after_rename.py << EOF
  > import os
  > import signal
  > from mercurial import extensions, util
  > 
  > def extsetup(ui):
  >     def close(orig, *args, **kwargs):
  >         path = util.normpath(args[0]._atomictempfile__name)
  >         r = orig(*args, **kwargs)
  >         if path.endswith(b'/.hg/store/data/file.i'):
  >             os.kill(os.getpid(), signal.SIGKILL)
  >         return r
  >     extensions.wrapfunction(util.atomictempfile, 'close', close)
  > def extsetup(ui):
  >     def rename(orig, src, dest, *args, **kwargs):
  >         path = util.normpath(dest)
  >         r = orig(src, dest, *args, **kwargs)
  >         if path.endswith(b'data/file.i'):
  >             os.kill(os.getpid(), signal.SIGKILL)
  >         return r
  >     extensions.wrapfunction(util, 'rename', rename)
  > EOF

  $ cat > $TESTTMP/killme.py << EOF
  > import os
  > import signal
  > 
  > def killme(ui, repo, hooktype, **kwargs):
  >     os.kill(os.getpid(), signal.SIGKILL)
  > EOF

  $ cat > $TESTTMP/reader_wait_split.py << EOF
  > import os
  > import signal
  > from mercurial import extensions, revlog, testing
  > def _wait_post_load(orig, self, *args, **kwargs):
  >     wait = b'data/file' in self.radix
  >     if wait:
  >         testing.wait_file(b"$TESTTMP/writer-revlog-split")
  >     r = orig(self, *args, **kwargs)
  >     if wait:
  >         testing.write_file(b"$TESTTMP/reader-index-read")
  >         testing.wait_file(b"$TESTTMP/writer-revlog-unsplit")
  >     return r
  > 
  > def extsetup(ui):
  >     extensions.wrapfunction(revlog.revlog, '_loadindex', _wait_post_load)
  > EOF

setup a repository for tests
----------------------------

  $ cat >> $HGRCPATH << EOF
  > [format]
  > revlog-compression=none
  > EOF

  $ hg init troffset-computation
  $ cd troffset-computation
  $ files="
  > file
  > Directory_With,Special%Char/Complex_File.babar
  > foo/bar/babar_celeste/foo
  > 1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/1234567890/f
  > some_dir/sub_dir/foo_bar
  > some_dir/sub_dir/foo_bar.i.s/tutu
  > "
  $ for f in $files; do
  >     mkdir -p `dirname $f`
  > done
  $ for f in $files; do
  >     printf '%20d' '1' > $f
  > done
  $ hg commit -Aqma
  $ for f in $files; do
  >     printf '%1024d' '1' > $f
  > done
  $ hg commit -Aqmb
  $ for f in $files; do
  >     printf '%20d' '1' > $f
  > done
  $ hg commit -Aqmc
  $ for f in $files; do
  >     dd if=/dev/zero of=$f bs=1k count=128 > /dev/null 2>&1
  > done
  $ hg commit -AqmD --traceback
  $ for f in $files; do
  >     dd if=/dev/zero of=$f bs=1k count=132 > /dev/null 2>&1
  > done
  $ hg commit -AqmD --traceback

Reference size:
  $ f -s file
  file: size=135168
  $ f -s .hg/store/data*/file*
  .hg/store/data/file.d: size=267307
  .hg/store/data/file.i: size=320

  $ cd ..


Test a hard crash after the file was split but before the transaction was committed
===================================================================================

Test offset computation to correctly factor in the index entries themselves.
Also test that the new data size has the correct size if the transaction is aborted
after the index has been replaced.

Test repo has commits a, b, c, D, where D is large (grows the revlog enough that it
transitions to non-inline storage). The clone initially has changes a, b
and will transition to non-inline storage when adding c, D.

If the transaction adding c, D is rolled back, then we don't undo the revlog split,
but truncate the index and the data to remove both c and D.


  $ hg clone --quiet --rev 1 troffset-computation troffset-computation-copy
  $ cd troffset-computation-copy

Reference size:
  $ f -s file
  file: size=1024
  $ f -s .hg/store/data*/file*
  .hg/store/data/file.i: size=1174

  $ cat > .hg/hgrc <<EOF
  > [hooks]
  > pretxnchangegroup = python:$TESTTMP/killme.py:killme
  > EOF
#if chg
  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  [255]
#else
  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  *Killed* (glob)
  [137]
#endif


The inline revlog still exist, but a split version exist next to it

  $ cat .hg/store/journal | tr '\0' ' ' | grep '\.s'
  data/some_dir/sub_dir/foo_bar.i.s/tutu.i 1174
  data/some_dir/sub_dir/foo_bar.i.s/tutu.d 0
  $ f -s .hg/store/data*/file*
  .hg/store/data-s/file: size=320
  .hg/store/data/file.d: size=267307
  .hg/store/data/file.i: size=132395


The first file.i entry should match the "Reference size" above.
The first file.d entry is the temporary record during the split,

A "temporary file" entry exist for the split index.

  $ cat .hg/store/journal | tr -s '\000' ' ' | grep data/file
  data/file.i 1174
  data/file.d 0
  $ cat .hg/store/journal.backupfiles | tr -s '\000' ' ' | tr -s '\00' ' '| grep 'data.*/file'
   data/file.i data/journal.backup.file.i 0
   data-s/file 0

recover is rolling the split back, the fncache is still valid

  $ hg recover
  rolling back interrupted transaction
  (verify step skipped, run `hg verify` to check your repository content)
  $ f -s .hg/store/data*/file*
  .hg/store/data/file.i: size=1174
  $ hg tip
  changeset:   1:64b04c8dc267
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     b
  
  $ hg verify -q
  $ hg debugrebuildfncache --only-data
  fncache already up to date
  $ hg verify -q
  $ cd ..

Test a hard crash right before the index is move into place
===========================================================

Now retry the procedure but intercept the rename of the index and check that
the journal does not contain the new index size. This demonstrates the edge case
where the data file is left as garbage.

  $ hg clone --quiet --rev 1 troffset-computation troffset-computation-copy2
  $ cd troffset-computation-copy2

Reference size:
  $ f -s file
  file: size=1024
  $ f -s .hg/store/data*/file*
  .hg/store/data/file.i: size=1174

  $ cat > .hg/hgrc <<EOF
  > [extensions]
  > intercept_rename = $TESTTMP/intercept_before_rename.py
  > EOF
#if chg
  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  [255]
#else
  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  *Killed* (glob)
  [137]
#endif

The inline revlog still exist, but a split version exist next to it

  $ f -s .hg/store/data*/file*
  .hg/store/data-s/file: size=320
  .hg/store/data/file.d: size=267307
  .hg/store/data/file.i: size=132395

  $ cat .hg/store/journal | tr -s '\000' ' ' | grep 'data.*/file'
  data/file.i 1174
  data/file.d 0

recover is rolling the split back, the fncache is still valid

  $ hg recover
  rolling back interrupted transaction
  (verify step skipped, run `hg verify` to check your repository content)
  $ f -s .hg/store/data*/file*
  .hg/store/data/file.i: size=1174
  $ hg tip
  changeset:   1:64b04c8dc267
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     b
  
  $ hg verify -q
  $ cd ..

Test a hard crash right after the index is move into place
===========================================================

Now retry the procedure but intercept the rename of the index.

  $ hg clone --quiet --rev 1 troffset-computation troffset-computation-crash-after-rename
  $ cd troffset-computation-crash-after-rename

Reference size:
  $ f -s file
  file: size=1024
  $ f -s .hg/store/data*/file*
  .hg/store/data/file.i: size=1174

  $ cat > .hg/hgrc <<EOF
  > [extensions]
  > intercept_rename = $TESTTMP/intercept_after_rename.py
  > EOF
#if chg
  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  [255]
#else
  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  *Killed* (glob)
  [137]
#endif

The inline revlog was over written on disk

  $ f -s .hg/store/data*/file*
  .hg/store/data/file.d: size=267307
  .hg/store/data/file.i: size=320

  $ cat .hg/store/journal | tr -s '\000' ' ' | grep 'data.*/file'
  data/file.i 1174
  data/file.d 0

recover is rolling the split back, the fncache is still valid

  $ hg recover
  rolling back interrupted transaction
  (verify step skipped, run `hg verify` to check your repository content)
  $ f -s .hg/store/data*/file*
  .hg/store/data/file.i: size=1174
  $ hg tip
  changeset:   1:64b04c8dc267
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     b
  
  $ hg verify -q
  $ cd ..

Have the transaction rollback itself without any hard crash
===========================================================


Repeat the original test but let hg rollback the transaction.

  $ hg clone --quiet --rev 1 troffset-computation troffset-computation-copy-rb
  $ cd troffset-computation-copy-rb
  $ cat > .hg/hgrc <<EOF
  > [hooks]
  > pretxnchangegroup = false
  > EOF
  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  transaction abort!
  rollback completed
  abort: pretxnchangegroup hook exited with status 1
  [40]

The split was rollback

  $ f -s .hg/store/data*/file*
  .hg/store/data/file.d: size=0
  .hg/store/data/file.i: size=1174


  $ hg tip
  changeset:   1:64b04c8dc267
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     b
  
  $ hg verify -q
  $ cd ..

Read race
=========

We check that a client that started reading a revlog (its index) after the
split and end reading (the data) after the rollback should be fine

  $ hg clone --quiet --rev 1 troffset-computation troffset-computation-race
  $ cd troffset-computation-race
  $ cat > .hg/hgrc <<EOF
  > [hooks]
  > pretxnchangegroup=$RUNTESTDIR/testlib/wait-on-file 5 $TESTTMP/reader-index-read $TESTTMP/writer-revlog-split
  > pretxnclose = false
  > EOF

start a reader

  $ hg cat --rev 0 file \
  > --config "extensions.wait_read=$TESTTMP/reader_wait_split.py" \
  > 2> $TESTTMP/reader.stderr \
  > > $TESTTMP/reader.stdout &

Do a failed pull in //

  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  transaction abort!
  rollback completed
  abort: pretxnclose hook exited with status 1
  [40]
  $ touch $TESTTMP/writer-revlog-unsplit
  $ wait

The reader should be fine
  $ cat $TESTTMP/reader.stderr
  $ cat $TESTTMP/reader.stdout
                     1 (no-eol)
  $ cd ..

pending hooks
=============

We checks that hooks properly see the inside of the transaction, while other process don't.

  $ hg clone --quiet --rev 1 troffset-computation troffset-computation-hooks
  $ cd troffset-computation-hooks
  $ cat > .hg/hgrc <<EOF
  > [hooks]
  > pretxnclose.01-echo = hg cat -r 'max(all())' file | f --size
  > pretxnclose.02-echo = $RUNTESTDIR/testlib/wait-on-file 5 $TESTTMP/hook-done $TESTTMP/hook-tr-ready
  > pretxnclose.03-abort = false
  > EOF

  $ (
  >   $RUNTESTDIR/testlib/wait-on-file 5 $TESTTMP/hook-tr-ready;\
  >   hg cat -r 'max(all())' file | f --size;\
  >   touch $TESTTMP/hook-done
  > ) >stdout 2>stderr &

  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  size=135168
  transaction abort!
  rollback completed
  abort: pretxnclose.03-abort hook exited with status 1
  [40]

  $ cat stdout
  size=1024
  $ cat stderr


  $ cd ..